Process and material for treating metal



been practical.

ALBERT n. ncnnninnn, or orrreaco, ILLINOIS, assrenon T0 tvrnnrnaa COZLWN,

or errrcaeo, rnnrn'ors.

ZP'RGGESS AND EMMLERIEAL FOR TREATING XVIETAL.

No Drawing.

1 0 all whom it may concern:

Be it known that l, ALBERT H. Aoxnn- MAN, a citizen if the United States, residing in Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Processes and Ma, teria-l for Treating Meta-l, of which the following isa specification.

My invention relates in general to the treatment of metals and has more particulan reference to the carburizing of metals, as, for example, is required in the case-hardening of steel. f

In the case-hardening of steel, the steel, after being formed, is treated in a closed chamber to cause absorption of carbon. This absorption is produced by lacing within the sealed chamber, along with the steel to be treated, a charge of charcoal and coke mixed with an energizer adapted to produce the carbon-monoxide gas, from which the carbon is absorbed into the iron. These cnergizers in the past have consisted large y of dried, ground animal. matter, as bones, hide, and the like, and none of them has proved entirely satisfactory.

The carburizing action with these compounds has required a degree of heat closely approaching the critical temperature of the metal so that the operation has been one of considerable delicacy and on this account of frequently disappointing results. Where the critical temperature is too closely approached or passed grain growth is produced in the steel which renders the product unfit for use. Other objections to the cornpounds usually employed prior to my invention for the carburizing of steel result from the circumstance, first, that the compounds are of uneven properties injecting an element of guesswork into the act1on as to the time of heat, degree of temperature, etc.; and, second, thecircumstance that the energizing capacity of thecompounds is relatively low and it has soon become exhausted in'use.

. A'principal object of my present invention isthe provision of an energizing material whichwill permit of the carburizing actioneither for the purpose of case-hardjeningor'for other purposes," at a substantially lower temperature-than has heretofore Application filed March 20, 1924. Serial No. 700316.

Another important object of the invention is the provision of an energizer, for the purposes described, '01 increased active power and which may be employed a relatively greater number of times before exhaustion.

Another important object of the invention is the provision of an energizer which will produce in the steel or other metal a material, after being mined, is or may be subjected 'to a treatment as follows: I

Dried at. or about 240 to 250 F, crushed to a granular form, and then dried again at.or under 300 F. The purpose of the initial drying in the process outlined above is merely to facilitate the crushing action. It may, however, be carried to a degree that will eliminate all of the moisture content, thus making unnecessary the second drying above mentioned.

Experiment has demonstrated thecircumstance that this phosphate rock accomplishes all of the purposes of the invention set forth herein and has other and further advantages,-as, for example, a smaller amount may be employed to produce a given carburizing result and less ash residue results from complete exhaustion of the material.

Experiment has also demonstrated that the arrangement 'of this material in the presence of carbon and the subjection of heat gives elf the desired energizing gases at lower temperatures than has heretofore been possibletemperatures at 1200 to 1400 F. accomplishing carburization and case-hardening heretofore only accomplished within practical limits of time by temperatures of from 1650 to 1800 F.

. An excellent and eficient mixture for the carburizing or case-hardening of steel has been found to be Per cent. Coke 25 Charcoal 35 Fossilized bone energizer 40 Such a mixture will liberate the necessary gases at a temperature Well below the critical temperature of the steel being treated, will carburize the material at a uniform rate, Will give a uniform carbon content prior to quenching, and will permit of use over and over again in the treatment of succeeding pieces of SUbJBCl', metal.

While the invention has hereinbefore been I claim:

1. A case-hardening composition, comprising, a mixture of rock phosphate, and a carboniferous substance.

2. A case-hardening composition, comprising, a mixture of desiccated, fossilized animal matter, and a carboniferous substance.

3. The process of case-hardening or carburizing metal, which comprises, arranging the metal to be carburizcd, and a carboniferous substance in a confined space and in the presence of rock phosphate, and heat ing.

4. The process of case-hardening or carburizing' metal, which comprises, arranging the metal to be carburized, and a Carboniferous substance in a confined space and in the presence of rock phosphate, and heat "ing to a temperature not to exceed 1400 F.

5. The process of case-hardening or carburizing metal, which comprises, arranging the metal to be carburizecl, and a mixture of a carboniferous substance and rock phos phate in a confined space, and heating.

' ALBERT H. ACKERBIAN. 

